Respuesta :

Answer:   3 F2  +  1 P2  ⇒ 2 PF3

Explanation:  

  Fluorine reduces from 0 ⇒ -I  and  Phosphor oxidises from 0 ⇒ + III

 But usually P is in form P or P4 (white or red Phosphor)

 So there need to be three F atoms receiving donated electrons from

one P atom. Then proportion F:P  =3:1